The invention relates to an antenna set-up comprising a first and a second reflector in the form of substantially parabolic cylinder surfaces and a feed source directed to the first reflector and placed on the focal line of that reflector and in which set-up the directrix of the cylindrical wave front obtained by exposure of the first reflector coincides with the focal line of the second reflector.
Such an antenna is known from the US-magazine "IRE Transactions Antennas and Propagation", Volime AP-3 No. 1 January 1955, Article by R. C. Spencer et al: "Double-Parabolic Cylinder pencil-beam antenna", pp. 4-8.
The antenna described in this literature reference has the drawback that the feed source is situated in the reflective beam on the surface of the second reflector and as a result exerts a disturbing effect on that beam.
U.S. Pat. No. 3,938,162, which describes a variable beam-width antenna of such a type, admittedly prevents the above drawback by placing the feed source on the edge of the second reflector out of reflective reach of the first reflector, but as a result in turn has the drawback that part of the second reflector cannot be used.